Apparatus for fused-bath electrolysis.



I Patentd May I3, I902. C. W. BOEPPEB & G. P. SGHOLLQ APPARATUS FORFUSED BATH ELECTBOLYSIS.

(Application filed Aug. 29, 189$. Renewed Och 15, 1901.1

(No Model.) 5 Sheets-Sheet I.

WITNESSES: INVENTORS THE Nonm's PEYiRS co. Pumo-umo" WASHINGTON, D c.

. No. 699,851. Patented May 13, |902.

c. w.- RUEPPER & a. P. SCHOLL.

APPARATUS FOR FUSED BATH ELECTROLYSIS.

(Application filed Aug. 29, 1898 Renewed Out 15', 1901.)

(No Model.) 5 Sheets-ShBBt 2.

i l W as l i i THE Nomus PETERS co. mo'mmwa. msumown. a, 'c.

No. 699,85l. Patented M'a'y l3, I902". C. W. RDEPPER & G. P. SCHULL.APPARATUS FOR FUSED BATH ELEGTBDLYSIS. (Application filed Aug. 29, 1898.Renewed Oct. 15, 1901.) (No Model.) 5 $heats$h68t 34 INViflIjTORS a fbil wiw iwfi JAM.

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WITNESSES:

No. 699,85l. PatentedM ay I3; I902. C. W. RDEPPER &. G. P. SCHULL.APPARATUS FDR FUSED BATH ELECTRDLYSIS.

(Application filed Aug. 29, 1898. Renewed Del. 15, 1901. (N Modem 5Sheets-Sheet 4,

. VENTORQ Ma i- 111 M 'l I cw 46% v 9 5 M THE norms PETERS 00..PHOTO-H1110" wnsmum'on. u c,

No. 699,851. Patented May l3, I902.

c. w. BOEPPER & a. P. SCHOLL.

' APPARATUS FOR FUSED B'ATH ELEC'TROLYSIS.

(Application filed Aug. 29, 189B. Renewed Oct. 15, 1901.)

(No Model.) 5 -Sheets-Sheat 5,

FIGS 1%.

n4: cams PETERs co., PHOTO-LI1HO., wnsnmarcu. u. c.

A UNTTET) STATES T ATnNT FFICE.

CHARLES W. nonrrna nn enonenr. SCI-IOLL, OF PI-IILADEL PllIAPENN-SYLVANIA; SAID SCHOLL ASSIGNOR TO SAID ROEPPER.-

APPARATUS FOR FUSED- -BATH ELECTROLY S I S.

SPECIFICATION forming part of Letters Eatent No. 699,851, dated May 13,1902.

Application filed August 29, 1898. Renewed October 15, 1901. Serial No.78,693. (No model.)

To ctZZ whom, it mag concern.-

Be it known thatwe, CHARLES W. ROEPPER, a citizen of the United States,and GEORGE P. SCHOLL, a subject of 'the Emperor of Gen many, residing atPhiladelphia, in the State of Pennsylvaniaghave invented a certain newand useful Apparatus for Fused-Bath Electrolysis, of which the followingis a specification.

I0 Our invention relates to an apparatus whereby the electrolysis offused substances may be economically conducted upon a large scale forthe purpose of producing commercially the products of such electrolysis.We

are aware of anumberof varieties of apparatus which have been used andsome of which have been patented for the purpose of conducting theelectrolysis of a bath the contents of which require to be heated to astate of fusion. All of these apparatus have developed defects whensubjected to the severe tests of use on a commercial scale. Under suchuse they have proved inadequate to withstand long-continued heat and therough handling of workmen. In some cases shaped clay vessels have beenused. 'These are fragile and incapable of undergoing the extremes oftemperature to which they must frequently be subjected. Furthermore, itis difficult to go obtain such vessels of sufficient size and strength.The use of such apparatus although attaining some success in thelaboratory has failed to solve satisfactorily the problem of thecommercial manufacture of the products of fused-bath electrolysis.

Our invention has overcome the defects presented by previous apparatusand results in the possibility of bringing the substances to andmaintaining them in a fused state 0 with a minimum expenditure of heat,assuring at the same time the continuity of the electrolytic operationby reason of the simplicityof construction of the'appa'ratus and theease with which its component parts can be repaired or exchanged.

Among the important features embodied in our invention may be mentionedthe partial, but only partial, separation of the chamber where theheating of the salts or other substances takes place from the chamberwhere the electrolysis is conducted; By partial separation we mean hereand throughout this specification a separation which while it does notin any way interfere with the uninterrupted intertlow of the materialsbetween the heating and electrolyticchambers, yet so far isolates theelectrolytic chamber as to permit access to and manipulation of theelectrolytic apparatus without interfering with the continuityof theheating process and withoutinterference with the operator by reason ofthe products of combustion; but while thus separating the electrolyticchamber from the heating-chamber for the purposes just explained weavoid the opposite extreme of having two wholly distinct vessels forthese two purposes with a mere pipe or similar connection. Such anarrangement is both uneconomical and impractical-uneconomical because ofthe loss of heat which takes place by reason of the circulation of airbetween the two vessels and-impractical because in man y instances a'narrowconnection between two such vessels is liable to freeze up.

Another important feature is the ready removability of the electrolyticapparatus for purposes of renewal or repair without interruption of thecontinuity of the fusion process.

Another such feature is the selection for contact with the fusedbath ofsuch durable and resistant material as to be capable of standing thedestructive action ofthe fused substances and other products. Theseresistant qualities are further supplemented by (a) a system ofjacketing used in connection with a cooling medium whereby a thinincrustation of the parts subject to the destructive action of the fusedbath maybe obtained with a consequent preservative action and (b) theselection of such shapes and sizes for parts liable to destruction as tomake them readily replaceable.

Another important feature of our apparatus which we desire to emphasizeat the outset is'that it admits of ready and economical 5reduplication-that is to say, it lends itself to varying constructionsin which a greater or less number of separate electrolytic compartmentsmay be grouped around and operated in conj uu ction with a sin gle largeheating and mo fusion chamber. In this way the utmost economy of fusionis combined with the largest output of electrolytic production.

In the accompanying drawings we have shown and we will now proceed todescribe a number of apparatus in which we have embodied in dififeringconstructions the principles which underlie our invention. It must beunderstood, however, that a large variety in the details of constructionis possible and that the specific constructions which we have describedare only typical. In some cases possible variations not shown will beadverted to; but in other respects the possible variations are sonumerous as to make it impossible to refer, to them all.

In the accompanying drawings, Figures 1, 2, 3, 4, 5, 6, 7, and 8illustrate both in its entirety and in some details a form of apparatusconstructed in accordance with our invention. This particular apparatusis a simple embodimentof it, and it will therefore be first described.Fig. 1 is a horizontal section along the line 1 1, Fig. 4. Fig. 2 is anillustration of the removable electrolytic box. Fig. 3 is a-forrn ofelectrode suitable for the collection of aliquid metallic elementresulting from the electrolysis. Fig. 4 is a vertical cross-sectionalong the line 4 4, Fig. 1. Fig. 5 is a vertical longitudinal sectionalong the line 5 5,

Fig. 4. Fig. 6 is a similar section along the line 6 6, Fig. 4. Fig. 7is a section of an electrodecompartment corresponding to that seen inFig. 4, but varying from it in detail. Fig. 8 illustrates an electrodein the form of a hollow squarej, which may be substituted for therod=sha-ped electrodes shown in Figs. 4, 6, and 7. Fig, 17 is a sectionof an electrode-compertinent, showing an electrode in the form ofshallow square inserted within it. Fig. 18 isa similar section in whichthe electrodes are shown arranged one within the other.

an a are" the walls and top of the furnace. These may be. built offire-brick or other refraetory' material.

A is the firing-door, B the grate, and O the fusion vessel.

Dis'the chimney by which the products of combustion are carried oif. Thebase E of this chimney formsa convenient mixing and preheatingcompartment, access thereto being had at the door a. It is within theeffective reach of the supply of heat, and by reason of its higher levelits contents when fused flow downinlto the fusion vessel. Thispreheatingcompartment may be otherwise located to suit convenience.

The fusion vessel 0 is considerably wider than the furnace and projectsthrough its sidev under the. arch 0. Along the line of this arch apartition F divides the fusion vessel into-two parts. This partition,although dipping weilbelow the normal level of the contentsof the fusionvessel-, does not reach the bottom of the vessel. It runs the wholelength of the vessel,dividing it into two parts,

which we will call the heating-chamber vided with a cooling-space;

'6. e., the part which is Within the furnace and the electrolyticchamber, which is the part which projects out of the furnace and wherethe electrolysis occurs. These chambers are alongside of each other andare designated in Fig. 1, respectively,fandf. Within the electrolyticchamberf' there fits a removable electrolytic bOX G. (Illustratedseparately in Fig. 2.) It is preferably made of cast-iron or steel andis open at the bottom, resting on two or more of its sides upon ledgesin the electrolytic chamber, which sustain it at the proper heighttherein. The space above the electrolytic chamber f may be inclosed bythinner walls 01 d, and the space between the top of the partition F andthe arch 0 may be closed by a clay plate d. These parts, however, arereadily removable.

It is essential that all the parts which come in contact with the fusedbath shall be made either of a highly-indestructible material orelseotherwise protected from the destructive action of the melted bath.Certain parts, indeedas, for instance, the walls of theelectrode-compartments about to be describedare so-arranged that ifdestroyed they may readily be replaced. To these the limitation whichhas just been mentioned does not so strongly apply. In order to preventthe destruction of the other parts which are subjected to the action ofthe heated bath, these parts are in the apparatus which is now beingdescribed surrounded by a cooling-space. Thus it will be noticed thatthe bottom and sides of the fusion vessel are surrounded withcooling-spaces g g g near their inner-surface. Inlet and outlet pipes gg communicate with these cooling-spaces and admit of a propercirculation of a cooling medium therein. Likewise the partition F ishollow and pro= The electrolytic box G is similarly constructed. Theresult of this cooling-jacket is that by a proper circulation of coolingmediums through the coolingspaces; the temperature of the sides of thefusion vessel and other parts which require protection may be keptslightly below the fusionpoint. Of course the difference in temperaturemust not be too great. It must be maintained, however, at such atemperature as to cause a constant slight incrustation on the sides andbottom of the bath. Under these circumstances the sides and bottom ofthe fusion vessel and of the partition and of the electrolytic box maybe made of metal or other substances which were they exposedcontinuously to the direct action of the molten bath would be destroyed,but being protected by a thin layer of inc-rustation are thus preserved.

The removable electrolyticbox G, is shown in Fig. 2. It is of such shapeas to fit loosely within the electrolytic chamberthat is, the part ofthe fusion vessel which is outside of the partition F. Within, the boxis lined with fire-brick or other suitable material and divided intoelectrode-compartments. Two

IIO

such parts only are shown; but the number is immaterial, correspondingto the convenience of the operation. To facilitate thisconstruction,theinnerwalls of the electrolyticbox are preferably made totaper slightly downward, so that the fitting of the fire-brick liningwithin it is easy,as well as its renewal,if necessary. To facilitate itsremoval,the electrolytic box is furnished with two trunnions h h orothersuitablesupports. Throughthesetrunnions,as shown in Fig. 2,t-heinlet and outlet of the cooling medium is conducted. To them also areattached the supports by which the electrolytic box is at will raisedand removed. from the apparatus for purposes of repair or substitution.This method of removal, as shown, consists of a trolley running on asuitable track, by which the box may be lifted and run out. The methodof elevation and removal is, however, immaterial. Any other convenientmethod may be employed. A desirable method of forming theseelectrodecompartments is shown in Fig. 1 and'Fig. 6, where the sides andends of the electrolytic box are shown fitted with flat plates h h h, offire clay or other suitable material, and similarly divided by apartition 77, the plates being simply blocked in position, anarrangement which is facilitated by the sloping sides of theelectrolytic box. In this way the replacement of any part of the sidesor partition which may be destroyed is very simply effected.Alternatively the entire lining of the box, including the partitions,may be formed from a single mold of fire-clay or other suitablematerial.

It is desirable that the lower inner edges of the lining shall have theinwardly-projecting ledges seen in Figs. i, 6, and 7. On these ledgeshollow electrodes or plates may be rested, thereby forming a liningwhich can act as electrodes.

The electrode-compartments of the removable electrolytic box as figuredin the drawings have been shown alongside of each other; but it is to beunderstood that the arrangement of these compartments may be varied tosuit the convenience of the operation, and they may be arranged onewithin the other, as is particularly shown in Fig. 18.

The details for the coverings for the electrode compartments and of theelectrodes within them must vary according to the electrolytic productwhich is to be obtained therein, depending consequently upon thecomposition of the fused bath. In the apparatus now under considerationseveral alternative forms are exhibited. Thus in Fig. 4 the electrodeboxwhich is seen has a dome-shaped cap fitting tightly upon it, with asuitable egresspipe. A single rod electrode projects down through thedome into the compartment. This is a convenient method of collecting agaseous element resulting from the electrolysis. Thus in theelectrolysis of chlorin salts chlorin gas is given off at the anode andmay be' thus collected, care being taken to form the cap and also allconnections of a material which will resist the action of the chloringas.

For a liquid element which will float upon the fused bath theelectrolytic chamber may be arranged as shown to the left in Fig. 6,where a flat top holds a dependent electrode. A suitable aperturepierces the side of the electrolytic box at a proper height to draw offthe liquid which may be formed.

In Fig. 8 an electrode in the form of a hollow square is shown. It maybe fitted within the electrode-compartment. In all of these forms itwill be understood that the description is wholly typical andexplanatory and not a matter of limitation.

Fig. 7 shows a construction having a similar purpose to that shown inFig. 4, differing in the flatness of its top and the arrangement of theconnections.

Fig. 3 shows a bell-shaped electrode which may be used. It may be formedof iron or any other proper material and will rest upon the projectingledges at the bottom of the electrode-compartment. By reason of itstapering shape a liquid formed by the electrolysis and floating on theelectrolyte is concentrated toward the top, filling it, and may be drawnofi through the exit seen at the top.

The operation of the apparatus thus far described is as follows: Theheated products of combustion passing from the grate through theheating-chamber acting upon the principle of a reverberatory furnacekeep the contents of the fusion vessel molten. In many instances gas oroil are more convenient to use than solid fuel. In some places also thegrate for solid fuel may be supplemented by these other means. The fusedloath maintaining its own level rises to equal height in theelectrolytic and fusion chamber, the partition F completely sealing theone from the other and preventing the escape of any of the products ofcombustion. In the electrolytic chamber the electrolytic box is loweredto a proper depth into the fused bath, its open bottom allowing the bathto come under the influence of the electrodes, none of the productsescapinginto the fusion-chamber. At any point during the operation andwithout materially interferin g with it the electrolytic box and itscontents may be removed for purposes of repair or otherwise and a newbox rapidly substituted. This may be done without lowering the level ofthe electrolyte, and consequently without interfering with thefusion-chamber in any way. If desired, however, at any time the fusedcontents may be withdrawn through a tap-hole (shown at. I, Fig. 4.) andrun 0% into any suitable receptacle. Before filling the fusion vesselthe electrolytic boxmay be raised, so that the heat can play over theentire surface and under and into the'electrovlytic box for preparatoryheating. The fusion vessel may then be gradually filled until itscontents have immersed the partitiomwall. o desire to here point out theeconomic duetive of heat.

horizontal sectionalong 1O 10, Fig. 9.

11 shows-in section similarto Fig. 9 an.alterother highly-refractorymaterial.

advantage of having the heating-chamber and the electrolyticchamber insuch close proximity and such open connection with each other. In thisway there is little or no loss of heat between the two, and it will benoticedtthat there is no uncontrolled air-space between the two, inwhich respect our apparatus differs in principle from all previousapparatus in which a separate heating vessel has been connected by apipe .or similar connection with .a separate electrolytic vessel. Wedesire to point out that we use the word 1 chamber in this applicationas denoting a subdivision of a common fusion vessel and in order todistinguish it from those apparaf tus in which the heating andtheelectrolysis take place in separate although connected vessels.

When it isdesirable-to preheator melt imaterials before adding them tothe main bath,

,it -can be done on the.preheating chamber E.

-With certain substances it is important. to

protect the fused bath from the products of combustion to prevent actionbetween them.

This we accomplish,among.other ways, by a layerof carbon, sand, ormelted slag lying upon the top .of the contents of the fusionl vesselwithin the heating-chamber and sufficiently thin :to allow readyradiation .of the heat therethrough. Any inert substance similar tothose which haverbeenenumerated may be used for the protection of thebath against .theactionof the gaseousproducts of described. The first ofthese is shown in. Figs. 9, 10, 11, and l2and is a suitable-formwhereaihigh'degree of heat is-requiredto effect fusion. Bythis arrangementthere are two iheating-tchambers, one on either side of the electrolyticchamber.

Fig. 9 is a verti cal section along 9 9, Fig. 10. Fig. 10 is a Fig.

nate method of supporting the removable electrolytic box. Fig. 12is avertical longitudinal section through 12 12, Fig. 10. As before, themain walls of the furnace shown in these'figures may be built of firebrick or In general outline the structure so formed consists of twofurnaces, supporteda short distancefrom each other, having a commonfusion vessel and'having the electrolytic chamber between electrolyticchamber.

ratus.

them. Each of the furnaces has its grate B, with its firing-door A. Cisthe fusion vessel, which, as seen in Figs. 9 and 12, runs across bothfurnaces adjacent to the grates and occupies also the interveningportion where is situated the electrolytic chamber. E E arepreheating-compartments. Where theinner wall of the furnaces crosses thefusion vessel two partial partitions F F are placed, which dip intothefusion vessel and divide it into three parts-namely, twoheating-chambers, one in each of the furnaces, and the Into theelectrolytic chamber there fits the removableelectrolytic box G,corresponding closely to the electrolytic box which has already beendescribed, and therefore no further detailed description need be givenof it beyond pointingout that it containselectrode-compartments andproper connections both for establishing the electric circuit and forcarrying off the products of electrolysis. As before, the removableelectrolytic box is supported by a flange which rests upona shoulderformed inthe partition walls. In Fig. 9 the position of the flange andshoulder is such that the support is at the .topof the box, while inFig. 11 an alternative form is shown, in which the support is near thebottom. the bottom of the partition forms a seal preventing the rise ofthe fused materials between the partition-walls and the box. When thebox is to be removed, either the level of the fused bath may be slightlylowered by tapping thebath and drawing off partof its contents, or bychecking the flow of thecooling medium through the hollow partitionwallstheir temperature may be allowed to rise temporarily, preventingincrustation during the interval between the removal of one box and thereplacement of another. For the purpose of removing the box anarrangement similar to that shown in Fig. 4 may be employed or any otherconvenient appa- Removal may take place by running the box backwardafter lifting, the space between the two furnaces being open in thatdirection. Immediately over the electrolytic chamber this-space is boxedin by removable partitions, as seen in Figs. 9 and 12. These partitionsare,.however, slightintheir nature. Throughthem pass the connectionsby-means of which the products of electrolysis are drawn ofi, which maybetemporarily broken when the box is to be removed. Under somecircumstances these walls surrounding the top of the electrolyticchamber may be entirely dispensed with. They serve merely to lessen theescape of heat atthe top of the electrolytic box and are only necessarywhen a very'high temperature is essential.

. In Figs. 13 and 14a further modification of the form which has justbeen described is shown. Fig. 13 is a vertical longitudinal sectionthrough 13 13 of Fig. 14. Fig. 14. is a hori- -zontal sectioncorresponding to Fig. 10, the

only difference being that instead of one re- In Fig. 11 the shoulderat.

movable electrolytic box two such boxes, end on and alongside of eachother, fill the electrolytic chamber. One of these is capable of beingremoved in one direction and the other in the other. In other respectsthe parts shown in this drawing correspond precisely to those shown inFig. 1.0 and are similarly lettered and need no further description. Thefusion vessel in this apparatus and in that last described may be formedof metal and shaped as seen in Figs. 9 and 12, the airspace being formedaround it by the space intervening between it and the walls of thefurnace. It has at each side sloping walls.

Fig. 15 is a construction in which the fused contents of the fusionvessel pass not only on either side of the electrolytic box, but allaround it, thereby facilitating a higher temperature therein. Thedrawing is a horizontal section corresponding to Figs. 14 and 10. Itdifiers from the construction shown in Fig. 14 in that instead of therebeing two furnaces there is but one, or rather the two have been unitedinto one, the electrolytic chamber being in this way surrounded on allsides, but not at the bottom, by the fusion vessel. With thisarrangement the removal of the electrolytic boxes is accomplished byraising up above the top of the end of the furnace (which is lower thanthe sides) and then sliding them forward or backward by an arrangementsuch as has been described. Although the grate is here shown as runningfrom side to side, a divided grate, as in Fig. 10, is often preferableto this form in order to leave room for more ready access to andconnection with the electrolytic boxes.

Fig. 16 is a diagrammatic sectional view showing a modification of ourinvention in which a number of removable electrolytic boxes are groupedaround a single heatingcompartment. The details of the construction arenot shown, as they will be readily understood to correspond with whathas been explained before. The central fusion vessel is heated in theusual way, and along its sides are partition-walls F, dipping below thelevel of the contents of the fused bath. On the outside of thesepartition-walls are the electrolytic chambers,alongside of each otherand some distance apart, six being shown in the drawings. In each ofthese electrolytic chambers is a removable electrolytic box, similar inconstruction to those already shown and described.

It will of course be understood that the plan shown in Fig. 16 is merelytypical and illustrative. There are very many ways in which a series ofelectrolytic compartments such as we have described may be convenientlygrouped around or within a centrally-disposed fused bath. Sucharrangements will readily suggest themselves to one skilled in the artand need not be here enumerated.

So far our apparatus has been described mainly with reference to heatingin the usual way by coal-fire, with the deflection of the heat and airand products of combustion downward along the entire surface of thefused bat-h. Other modes may be employed either by themselves or inconjunction with a grate-fire. Under many circumstances oil or gas areadmirably adapted for this purpose. Thus in Fig. 16 the heat produced bythe grate-fire maybe supplemented by the introduction of gas or oilburners at thesides, passing, for instance, between the electrolyticcompartments, and by means of these burners gas or oil may be burned andthe heat of the entire heating-compartment increased.

In describing the apparatus thus far it has been assumed that theproducts of the electrolysis, whether gaseous or liquid, were lighter inspecific gravity than the fused bath and would therefore float on top ofit in the region of the electrodes, where they are liberated.Corresponding means for removing these products have been shown. Undercertain circumstances, however, one or more of the products of theelectrolysis may be a heavier fiuid or a precipitate. In such cases theremoval of this product from the bottom of the fused bath may beeffected by a tap-hole properly situated.

Having thus described our invention, we claim- 1. In an apparatus forthe electrolysis of fused substances, the combination of a Vessel forcontaining fusible substances; a heating-chamber of smaller dimensionsthan said vessel, but of which a portion of said vessel forms thebottom, and means in said heatingchamber for reducing the contents ofsaid vessel to fusion; a partition forming one of the said walls of theheating-chamber which extends below the normal level of the fusedcontents of said vessel but does not reach to its bottom; anelectrolytic chamber outside but immediately alongside of theheating-chamber separated from it only by said partial partition, therebeing no uncontrolled air-space between the two; and means consisting ofpositive and negative electrodes situated within said electrolyticchamber, and wholly exterior to the heating-chamber, for carrying ontheelectrolysis of the fused contents of the vessel.

2. In an apparatus for the electrolysis of fused substances, thecombination of a heating-chamber in the form of a reverberatory furnace;a vessel for containing fused substances over which the products ofcombustion in the reverberatory furnace play, said fusion vesselextending at one side of the heating-chamber beyond its walls; apartition forming the last-mentioned side of the heating-chamber whichextends below the normal level of the contents of said fusion vessel butwhich does not reach to its bottom; and means for conductingelectrolysis of the contents of said fusion vessel situated whollyoutside of said partial partition, substantially as described.

3. In an apparatus for the electrolysis of fused substances, thecombination of a heating-chamber in the form of a reverberatory furnace;a vessel for containing fused substances over which the products ofcombustion in the reverberatory furnace play, said I fusion vesselextending at one side of the heating-chamber beyond its walls; apartition forming the last-mentioned side of the heating-chamber whichextends below the normal level of the contents of said fusion vessel butwhich does not reach to its bottom; a separate electrolytic box open atthe bottom and carrying positive and negativeelectrodes and fittingremovably into that part of the fusion vessel which is situated outsideof the heating-chamber, substantially as described.

4. In an apparatus for the electrolysis of fused substances, thecombination of a fusion vessel; means whereby products of combustion arecaused to play over the surface of all but a restricted portion of thecon-tents of said fusionvessel; one or more vertical partitionsextending below the normal level of the contents of said fusion vesselwholly isolating the said restricted portion of the contents of saidfusion vessel from the products of combustion whereby free access tosaid restricted portion may be had; a removable electrolytic box, openat the bottom, carrying positive and negative electrodes; and means forbringing said electrolytic box into or out of contact with thecontentsof the fusion vessel within said restricted portion,

substantially as described.

5. In an apparatus for the electrolysis of fused substances, thecombination of a fusion vessel and means for heating the contentsthereof; a separate electrolytic box, open at the bottom, and carryingattached to itself both positive and negative electrodes; and

means for placing said-electrolytic box within a portion of said fusionvessel with its bottom dipping beneath the contents thereof and removingit therefrom, substantially as described.

6. In an apparatus for. the electrolysis of fusedsubsta-nces, thecombination of a fusion vessel; means forheatingitscontents; aseparateelectrolytic box open at the bottom removable therefrom carryingpositive and negative electrodes and having hollow walls with means formaintaining circulation of a suitable fluid medium through said walls,substantially as described.

7-. Inan apparatus for the electrolysis of fused substances,the-combination of a fusion vessel; vertical partitions extending belowthe normal level of the contents of the fusion vessel and dividing itinto a centrally-located heating-chamber and a series of electrolyticchambers grouped around said heating-chamber; means situated within saidheatingchamber for heating the contents of the fusion vessel; and aseries of electrodes situated wholly with-in said electrolytic chamberwhereby electrolysis may be carried on therein, substantially asdescribed.

8. In an apparatus for the electrolysis of fused substances, thecombination of afusion vessel; means for heating the contents of saidvessel; a preheating-chamber within the effective reach of the source ofheat provided with a bottom above the normal level of the contents ofthe fusion vessel into which the contents of the preheatingchamber whenfused will fiow down; and electrodesim mersed in the contents of thefusion vessel, substantial-1y as described.

9. In an apparatus for the electrolysis of fused substances, thecombination of a fusion vessel; means for heating its contents; aremovable open-bottomed electrolytic box carrying electrodes, fittinginto the fusion vessel; and lodges on the side of the fusion vesselbelow the normal level of its contents upon which the electrolytic boxrests and which are arranged to seal the outside of the box from thecontents of the fusion vessel, substantially as described.

10. In an apparatus for the electrolysis of fused substances, thecombination of the fusion vessel; means for heatingits con-tents; anopen-bottomed removable electrolytic box carrying electrodes; and blocksof fire-clay, or similar resistant material, fitted removably around theinside of the electrolytic box and forming the lining thereof,substantially as described.

11. In an apparatus for the electrolysis of fused substances, thecombination of a fusion vessel; two vertical partitions extending belowthe normal level of the contents of the fusion vessel, but not reachingto its bottom, forming three separate chambers above :the fusion vessel,one at each end and one in the center; means situated within each of theend chambers for heating the-contents of the fusion vessel; and one ormore openebottomed electrolytic boxes carrying electrodes fittedremovably within the central chamber, substantially as described.

August 22, 1898.

CHARLES W. ROEPPER. GEORGE P. SCHOLL.

Witnesses:

JAMES H. BELL, RANDOLPH SAI-LER.

